JP2010107075A - Gas cooking stove - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems in a gas cooking stove wherein it takes a long time to reduce heat to a minimum fire power state as conventionally a reduction speed is lowered before reaching the minimum fire power state to slowly reduce a gas supply amount, as misfire may occur when the fire power of the gas burner is rapidly decreased to the minimum fire power state, meanwhile, in a case when a temperature of the gas burner is low, misfire often occurs, while the misfire is reduced in accompany with temperature rise. <P>SOLUTION: The misfire is prevented by temporarily stopping or decelerating reducing motion when the temperature is lower than a prescribed temperature based on the temperature of the gas burner. Further even in the case when the temperature is lower than the prescribed temperature, the higher the temperature is, the smaller a deceleration rate is, and a temporal stop time is shortened. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a gas stove that increases or decreases a gas supply amount to a gas burner stepwise by a motor in accordance with a user's heating power adjustment operation.

  As a conventional gas stove of this type, for example, a gas stove including a flow rate control unit that controls the flow rate of gas, a drive unit that uses a stepping motor that drives the flow rate control unit, and a drive control unit that drives and controls the drive unit. It has been known.

  When the gas flow rate is controlled by a stepping motor in this way, if the throttle speed when the flow rate is reduced to the minimum thermal power is high, the reduction speed of the combustion air cannot catch up with the gas reduction speed, so the air temporarily It becomes an excessive state. Therefore, the malfunction that misfire occurs with a gas burner arises.

Therefore, the gas throttle speed is decelerated before the gas throttle amount reaches the minimum thermal power state so that the reduction speed of the combustion air can follow the gas reduction speed (see, for example, Patent Document 1). .
JP 2000-179839 A (Claim 2)

  In the above configuration, since the gas throttle speed is reduced until the minimum thermal power is reached, it takes a long time to reduce the gas to the minimum thermal power state, and from the user's point of view, the thermal power adjustment knob is set to the minimum thermal power state. Even after the operation is completed, the firepower is gradually reduced, which is not desirable from the standpoint of use. In addition, there is a problem that such deceleration speed reduction control is performed every time an operation for setting the heating power adjustment knob to the minimum heating power is performed.

  On the other hand, it does not necessarily misfire when it is rapidly squeezed to the minimum thermal power state. If the temperature of the gas burner is low, the heat of the combustion flame is taken around the flame burner's flame mouth and the flame holding power decreases, so it is easy to misfire, but if the gas burner is warm, the flame holding power is large, so the minimum The possibility of misfire is very low even if the firepower condition is rapidly reduced.

  Then, this invention makes it a subject to provide the gas stove which prevents misfire only when there exists a possibility of misfire when it restrict | squeezes to the minimum heat power state in view of said problem.

  In order to solve the above problems, a gas stove according to the present invention has a temperature detection means for determining the temperature of a gas burner in a gas stove that increases or decreases the amount of gas supplied to the gas burner by a motor in accordance with a user's heating power adjustment operation. When operation is performed to reduce the thermal power to the minimum thermal power when the temperature is lower than the specified temperature, the throttle speed is reduced before the gas throttle amount reaches the minimum thermal power state, and the throttle speed after deceleration is minimized. It is characterized in that it is brought into a thermal power state or once stopped and then throttled to a minimum thermal power state.

  As described above, the flame holding power of the gas burner differs depending on the temperature of the gas burner. Therefore, when the throttle operation to the minimum thermal power is performed, if the flame holding power is small, that is, if the gas burner temperature is lower than the predetermined temperature, the throttle speed is reduced, or the throttle is once throttled before reaching the minimum thermal power state. The operation was stopped so that the combustion air was not excessive for the gas supplied to the gas burner.

  The temperature of the gas burner can be directly detected by attaching a temperature detection sensor such as a thermocouple to the gas burner. However, the temperature detection means estimates the temperature of the gas burner from the duration of the ignition state of the gas burner, and the temperature of the gas burner. You may comprise as follows.

  Since the gas burner warms faster as the heating power increases, the temperature detecting means may estimate the temperature of the gas burner based on the magnitude of the heating power in addition to the duration when the temperature of the gas burner is estimated.

  Further, when the gas burner is ignited again in a short time after the use of the gas burner is stopped, the gas burner is already preheated to some extent at the time of re-ignition. Therefore, the preheating temperature of the gas burner at the time of reignition is obtained from the temperature of the gas burner when the gas burner is extinguished and the time until reignition, and this preheating temperature is added when estimating the temperature of the gas burner. It is desirable.

  Furthermore, the necessity of decelerating the throttle speed or temporarily stopping is greater as the temperature of the gas burner is lower. Therefore, when the throttle speed is decelerated or temporarily stopped, the throttle speed after deceleration may be slowed down or the time for which the gas burner is temporarily stopped longer as the gas burner temperature is lower.

  As is clear from the above description, the present invention is not limited to the minimum thermal power state at a stroke even if the operation is performed to the minimum thermal power state in the state where the possibility of misfire is high, that is, the temperature of the gas burner is low. Is reduced, or once the throttle speed is reduced to zero before reaching the minimum thermal power state, misfire is prevented. However, if the throttle speed is decelerated or once stopped, the throttle operation by the user does not match the actual thermal power, and it takes extra time to reach the minimum thermal power state. In the present application, the above-described deceleration or temporary stop is not performed in a state where the temperature of the gas burner is high and there is almost no risk of misfire, so that unnecessary deceleration or temporary stop is not performed.

  With reference to FIG. 1, 1 is an example of a gas stove according to the present invention. The gas stove 1 is provided with three large, medium and small gas burners 21, 22, and 23 on the upper surface. The heating power of each of these gas burners 21, 22, 23 is performed by the heating power adjustment knobs 11, 12, 13. In addition to the above three gas burners 21, 22, and 23, the gas stove 1 is provided with a grill box 14, and the gas burner in the grill box 14 is operated by a heating power adjustment knob 15.

  A potentiometer such as a rotary encoder that detects a rotation angle is attached to each of the heating power adjustment knobs 11, 12, 13, and 15, and is configured to detect a rotation operation amount for adjusting the heating power. .

  With reference to FIG. 2, gas is supplied to each gas burner 21, 22, 23 through gas supply pipes 31, 32, 33 branched downstream of the original solenoid valve 3. Each gas supply pipe 31, 32, 33 is provided with a thermal power control unit 41, 42, 43, respectively. These thermal power adjustment units 41, 42, 43 are driven by stepping motors 51, 52, 53 that are driven and controlled by the control unit 6. That is, the gas flow rates of the gas supply pipes 31, 32, and 33 are increased and decreased by the stepping motors 51, 52, and 53, respectively.

  For example, when the thermal power adjustment knob 11 is rotated for thermal power adjustment, a detection signal corresponding to the rotational operation amount is input to the control unit 6. Then, the control unit 6 obtains a target heating power from the rotation operation amount, and drives the stepping motor 51 so as to obtain a gas flow rate corresponding to the heating power. Then, the amount of restriction of the thermal power adjustment unit 41 changes, and the flow rate of gas supplied to the gas burner 21 changes.

  The control unit 6 is programmed to estimate the temperature of each of the gas burners 21, 22, 23. Referring to FIG. 3, when the heating power is set at 9 levels, the change in heating power from the start of ignition is monitored, and the product of each heating power and time is set as the temperature of the gas burner. That is, the area shown by the oblique lines in FIG. 3 is the temperature of the gas burner. However, when the temperature of the gas burner reaches the preset maximum temperature Tmax, the temperature of the gas burner is set to be constant at Tmax, assuming that the temperature does not rise any further.

  In addition, when the gas burner is heated and the fire extinguishing operation is performed in a state where the temperature is increased, the temperature of the gas burner is decreased. The temperature of the gas burner obtained in FIG. 4 was added.

  In FIG. 4, the cooling rate of the gas burner is approximated to a straight line. The cooling rate was fast until t1 elapsed from the time when the fire was extinguished, but after t1, the cooling rate became slow, and at time t2, the gas burner was set to be cooled to near room temperature.

  From FIG. 4, based on the temperature when the gas burner was extinguished, the temperature of the gas burner was obtained by slowing down the cooling rate before and after the lapse of t1, and the preheating temperature was added when estimating the temperature of the gas burner after reignition It was decided to.

  Based on the above configuration, the thermal power control of the gas stove 1 will be described with reference to FIG. For example, when the thermal power adjustment knob 11 is turned, the control unit 6 obtains the thermal power after the operation as described above. Then, before driving the stepping motor 51, it is determined whether the current heating power is 3 or more (S1). The misfire in the gas burner is caused when the gas supply amount is rapidly reduced, and when the state shifts from a thermal power of 3 or more to the thermal power of 1. Therefore, if the heating power before changing the heating power is 1 or 2, there is no fear of misfire. Therefore, there is no risk of misfire if the current thermal power is less than 3, so the normal stepping motor is driven at a normal speed so that the thermal power is controlled by the normal thermal power control, that is, the thermal power control knob. The amount of gas supplied to the gas burner is increased or decreased (S8).

  If the current thermal power is 3 or more, there is no risk of misfire unless the operated thermal power is 1. Therefore, if the operated thermal power is other than 1 (S2), normal thermal power control is performed (S8).

  That is, when an operation for changing the heating power from 3 to 5 is performed, the temperature of the gas burner is calculated from the product of the duration after the gas burner is ignited and the set heating power (S3). ). In the case of reignition, the above preheating temperature is added. When the temperature of the gas burner is lower than the predetermined temperature (S4), the stop time is calculated (S5), and the stepping motor is temporarily stopped for the stop time calculated in S5 from the time when the state of the thermal power 2 is reached. I did it. On the other hand, when the temperature of the gas burner is higher than the predetermined temperature, normal thermal power control is performed (S4, S8).

  When calculating the stop time in step (S5), the gas burner temperature is used to set the stop time longer as the gas burner temperature is lower. The higher the gas burner temperature is, the shorter the stop time is. It may be 0.

  Then, during the stop time calculated according to the temperature of the gas burner in this manner, the stepping motor is again driven so as to become the operation heating power after temporarily stopping at the heating power 2 (S7).

  In the flow shown in FIG. 5, when the thermal power is reduced from the state of 3 or higher to the thermal power 1, the throttle operation is temporarily stopped by the thermal power 2, but the gas burner temperature is the predetermined temperature at the transition speed from the thermal power 2 to the thermal power 1. If the temperature is lower, the vehicle may be decelerated, and the degree of deceleration may be controlled to increase as the temperature of the gas burner decreases. That is, as the gas burner is colder, the throttle speed at which the thermal power 2 is transferred to the thermal power 1 is lowered, and the throttle speed from the thermal power 2 to the thermal power 1 is made closer to the normal throttle speed as the temperature of the gas burner increases. May be.

  In the above embodiment, the temperature of the gas burner is estimated from the product of the duration of the ignition state and the thermal power. However, the temperature of the gas burner may be estimated only by the duration without including the thermal power as a condition. Alternatively, when the calculated temperature of the gas burner is lower than a predetermined temperature, the stop time may be uniformly set to a constant time. Further, the temperature of the gas burner may be estimated by an electromotive force of a thermocouple disposed in the vicinity of the gas burner, or may be detected by a temperature sensor attached in contact with the gas burner. Moreover, in the said embodiment, although the thermal power was installed in nine steps, you may apply this invention to what adjusts a thermal power by increasing / decreasing gas continuously.

  The present invention is not limited to the embodiment described above, and various modifications may be made without departing from the scope of the present invention.

The figure which shows the structure of one embodiment of this invention Block diagram showing internal configuration of gas stove Diagram showing the estimation method of gas burner temperature Diagram showing gas burner cooling rate Flow chart showing aperture speed control

Explanation of symbols

1 Gas stove 6 Control unit 21, 22, 23 Gas burner 41, 42, 43 Thermal power control unit 51, 52, 53 Stepping motor

Claims (5)

  In the gas stove that increases or decreases the gas supply amount to the gas burner by the motor according to the user's heating power adjustment operation, it has temperature detection means to determine the temperature of the gas burner, and the thermal power is minimized when the gas burner temperature is lower than the predetermined temperature When the throttle operation is performed until the gas throttle amount reaches the minimum thermal power state, the throttle speed is reduced to the minimum thermal power state at the throttle speed after deceleration, or the temporary thermal power state after stopping once Gas stove characterized by squeezing up to.   The gas stove according to claim 1, wherein the temperature detection means estimates the temperature of the gas burner from the duration of the ignition state of the gas burner and sets it as the temperature of the gas burner.   The gas stove according to claim 2, wherein the temperature detecting means estimates the temperature of the gas burner based on the magnitude of the heating power in addition to the duration when the temperature of the gas burner is estimated.   The preheating temperature of the gas burner at the time of reignition is obtained from the temperature of the gas burner at the time when the gas burner is extinguished and the time until reignition, and this preheating temperature is added when estimating the temperature of the gas burner. The gas stove according to claim 2 or 3, characterized by the above.   5. When the throttle speed is decelerated or temporarily stopped, as the gas burner temperature is lower, the throttle speed after deceleration is slowed or the time for temporarily stopping is lengthened. A gas stove according to any one of the above.

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